Hey guys, I have confirmed with the powers that be at ASUS that they will be releasing a new and improved driver set the the public for the STX/ST.

Yes, they will provide "bit perfect" output.

These new drivers are low latency and based on what I have seen they provide some very impressive numbers in comparison to previous releases.

While still in early Beta stage they provide what some of you have been after, using ASIO to acheive bit perfect output. There are a few other details the you might find interesting about the driver but I don't want to release all the surprises...

The Asus Xonar Essence STX is a PCI-E audio card designed for high-end computer-based audio playback. It has many interesting features such as:

* Burr Brown 1792A DAC chips offering -124db Real world performance.
* Independent power sources for line and headphone outputs keeping the signal clean and clear and eliminating any interference between output sections.
* Swappable opamps – You can fine tune your sound quality on the Essence using higher quality opamps or tune to your liking using your favorite units. The card is outfitted with LM4562 and JRC 2114D’s stock build.
* EMI shielding - the sensitive analog electronics are sealed and protected from harmful EMI/RFI behind a carefully designed shield.
* New hyper grounding circuitry design allows sensitive analog paths to be isolated on the circuit board keeping them free from noise and interference.
* Nichicon “Fine Gold” Professional audio capacitors offer rich bass and crystal clear high frequencies.
* Built in high quality, high impedance TI TPA6120A2 with software settable gain ranges allowing for high quality headphones to be used without external amplification units.

Essentially Asus has created an audio card that cost less than $200 that can provide an EXTREMELY high quality signal directly to headphones, an external headphone amp, or powered speakers. Swappable opamps mean users can tailor the sound to match their listening desires and equipment.

FAQ:Q: Is this card better than XXX other card?
A: While that's pretty impossible to answer, it's damn good for the price. It can power pretty much any headphone you can plug into it and sounds phenomenal. You can swap opamps to match your listening desires or the strengths or weaknesses of your headphones or speakers. It easily matches up to external DACs/amps costing far more (although you obviously lose the portability those have). It's likely better than most other sound cards in the price range (it's probably safe to say the E-MU 1212m is superior for less money), but when you add in the quality headphone amplifier it's certainly better than any sound card in the price range (that I know of).

Q: What is the difference between the ST and the STX?
A: The ST is a PCI compatible card, the STX is a PCI-E compatible card. The ST has a "better clock" which concievable leads to "less jitter". People report that they have distinctly different sounds that can easily be discerned. The ST also has an optional daughterboard that allows for analog 7.1 output. Rather than post anything more, I'll just link out to some of the threads I have found:

Q: Can the Essence STX run in a PCI-E 16x slot?
A: Yes, PCI-E cards are all upwards compatible. A 1x, 4x, or 8x card can be run in a 16x slot. I run mine in a PCI-E 16x slot. It cannot run in a standard PCI slot.

Q: What's the deal with interchangeable opamps?
A: The card has 3 swappable 8-pin dual opamps. The two matched I/V opamps impact the headphone out alone, while the 3rd "buffer" opamp impacts the RCA out. If you are only using the headphone out you only have to worry about the 2 I/V opamps. They can be removed and replaced using your fingers, a small flathead screwdriver, needle nose pliers, etc.

Q: What opamps are people using in this card?
A: Here are a variety of quotes from users:

Quote:

Originally Posted by Funky-kun

Talking about opamps, I think I've ended my quest for the perfect ones. Here are my impressions. All testing done through HP out with HD650s.

JRC2114 (default) : I actually think the default opamp for the card is a really good choice. Had it not been for the bassy and dark signature of my cans, I would have kept these. They actually sound the best with my HD595s. Bass is very deep, with perfect extension, just a bit too much in quality for the HD650s. The highs tend to be a bit rolled off, and the soundstage is pretty wide, but not deep and high. I imagine these would sound fantastic with headphones like K701/2 or DT880, but is too heavy for my current cans.

LT1364 : I didn't like these very much. Bass seems neutral, but lacks punch. Mid and highs are well balanced, but soundstage isn't that much better than 2114. Detail is improved. Sounds too weightless.

OPA2134 : Disappointment. As Alienns stated, the default opamps are just better. These have more bass, but the quality is degraded in comparison. With these opamps the bass on 650s sounded like the one on my HD212. (read: boomy) Highs are also rolled off. The soundstage isn't impressive, but opens a bit after burn-in. Sounded "dense", in the sense that all the sounds are too close to you and without good positioning.

LME49720 : All I can say is these babies ROCK. Bass lacks just a little bit of extension, but is very natural sounding and punchy. Highs are brighter than average, but that cancels out with the dark signature of my headphones well, resulting in an overall neutral tonality. Soundstage is absolutely awesome. You can easily position instruments in direction and distance. Has the depth other opamps are missing. All details are clearly present, but the sound is a bit distant due to the soundstaging. My current and final choice.

LM6172 : These are very close in sound to the LME49720. Biggest difference is that they aren't so distant sounding. That means less soundstage and a bit better bass. I didn't find the trade off worthwhile. Still a very valid choice.

I hope all of you find the perfect opamp match for your headphones. I have done it.

Quote:

Originally Posted by Shahrose

Update once again on opamps. I've found that no matter which opamp is used in the buffer spot, if there are 2xLME49720 in the I/V section, the bass output is compromised. The bass can be tight or loose depending on the buffer, but it lacks punch no matter which buffer amp is used (relative to default opamps and OPA2107).
So now I'm using the LME49720 in the buffer spot and 2xOPA2107 in the I/V section. The soundstage is about the size of stock (nothing like 2x49720 in the I/V), but the bass is the best I've heard quality-wise, and is in plentiful quantity. The highs are more prominent as well but, unfortunately, they're scratchy/grainy (not smooth) and at times, quite fatiguing. However, the main benefit of this setup is that the overall transient response is noticeably improved over all other opamp combinations and it really produces a detailed, quick, high-energy sound.

At low volumes, this setup sounds good, but at high volumes, I prefer the LME49720 in the I/V section. I wish I could combine the bass/transient speed of the OPA2107 with the smooth treble and huge soundstage of the LME49720.

Quote:

Originally Posted by riderforever

Hi guys, sorry for having been away from this thread for a little while, but now I'm back

In the meanwhile two important things have simple revolutioned the playback of my audio system:

First of all, let me speak about the latter: I strongly advice all of you who do listen through speakers to try it, you won't listen without it anymore for sure. It simply removes any bump or enphasis due to amp-speaker-environment combination and its effect is smashing expecially on the bass frequencies. The gain in terms of impact, articulation and extension is unbelievable.
With the digital correction in place I was finally able to rightly evaluate the opamps.

To me the LM49720NA as I/V are really great opamps and a noticeable step forward with respect to the JRC. I was suprised not to feel any particular loss of bass, instead it becomes tighter. In general the sound is much more defined without any harshness and very enjoyable to listen.
Then I put back the Burson opa-101 in the buffer place and I started again to hear marvellous things: lots and lots of details are unveiled in - practically - every track, the sound is absolutely natural and flows out of the speakers with a fluency and liquidity which is unknown to my ears. And - most important - with the digital filtering ON the bass is absolutely in pair with mids and highs, furthermore it has an impact and articulation just perfect (at high volumes I can feel it through my body), without any issue regarding extension.

I don't know if the Burson is worth its price and there is a considerable difference with respect to be Audio-Gd ones, but - trust me - you should try a discrete opamp, they have some kind of magic.

Quote:

Originally Posted by Alydon

Ultimately with my rig, using a 6172 in the buffer sounds the most realistic to me.. In my setup, the 6172 has the most detailed, full-bodied, and visceral bass of any opamp I've tried (including the JRC2114, which by comparison had a smeared, boomy, and indistinct bass), whereas the 49720, though detailed, is missing the lowest bass registers and simply doesn't have the impact or imaging that the 6172 provides. This is especially noticeable with strings and percussion. There is also a little too much upper-mid/lower treble emphasis (1-2KHz) with a 49720 buffer that makes horns sound slightly “bleaty” and gives high strings and pianos a nasal quality that sounds somewhat off to me (though again I don't think that the HD650's would experience this).

Lastly, I personally prefer the more intimate soundstage that gives me the feel of being in amongst the musicians. The 3x49720's setup does have a larger soundstage and I can see where many might prefer it, but it made the musicians a little too far away and the music a little detached as a result to be ideal for me.

Overall, both opamps are excellent choices though and I'd still be quite content w/ a 49720 in the buffer if the 6172's didn't exist. I strongly suggest to anyone that wishes to try their hand at opamp rolling on the STX that you try both of these opamps in the buffer spot to find out which one you prefer since I don't believe one is superior to the other. I guess this goes to show how important system synergy and personal preference come into play in addition to the personal experience and compromise/balancing that Shahrose already mentioned...

...

However, since I don't seem to be able to leave well-enough alone, I've been rolling opamps in my Corda Opera and I think I've found another one that I'd like to try in the STX as well: the LM7171. This is a single-channel opamp which means you’ll need to use two of them on an adapter. However, they seem quite promising given the results I’ve heard from the Opera.

So far in the Opera it sounds very similar to the stock 6171's that it comes with, but with the contrast turned up. It has a blacker background, and slightly better dynamics, deeper and cleaner bass, a deeper soundstage, and better imaging. The mid-bass hump is reduced as well. Once my adapters arrive in the mail I’ll test them out in both the buffer and I/V spots of the STX to see how they fare.

Quote:

Originally Posted by Shahrose

I don't want to say I like or don't like. I want to try to give as accurate a description of their sound as possible so others can decide. My own subjective preferences are always in a flux and one day I can like something and the next I'll be disappointed with it.

The LME49720 in the buffer spot sound smooth, with prominent mids and have tight hard-hitting bass. The soundstage is also wide.

In the I/V their bass is not as defined as stock, it's also less prominent, and less extended (slightly). They also produce a slow sound so certain harmonics have a longer decay. This gives a nice ambient/airy sound that results in a nice soundstage but this effect is also the culprit for their slow sound. The treble is excellent though, not harsh at all yet extended and grain-free.

So far, if you were to ask me what I like most out of every combination I've tried so far. It would be the 1xLME49720 / 2xJRC2114. Overall these have the least number of flaws and I keep going back to them. A couple other combinations sound almost as good but just don't suit my preferences.

Quote:

Originally Posted by Telix

I have been running 2x LME49720's for a few days and today swapped in 2x LM6172's (I use the headphone out). With the Denon's the LM6172's had too much uncontrolled bass. Even the LME49720's can feel a little flabby with certain bass-heavy music (I'd attribute that to the Denon's before blaming the opamp...) but the LM6172's were simply not a good match to my partially modded Denon's.

Just tried other combinations:
2хJRC2114D + LM6172IN = sound is bold and low-detailed, but the bass hit well.
2xJRC2114D + LME49720NA = powerful bass, harsh sound, different from the HP-out's sound - a little less pointed treble and greater detail..
Now listen again 2xLME49720NA + LM6172IN, still more pleasant sound, not as harsh as the previous combination, but also with good bass. I'll stay with this combination.

By the way, LM6172, in contrast to the LM4562, have flatter graph of noise in the treble zone.

Added: Listening music full evening... Everything sounds great.

Quote:

Originally Posted by johnzz4

Just tried a few op amps and settled on the 49720HA's on adapters in the IV and the one of the stock JRE's in the buffer. Sounds great....

Also tried different combinations with OPA2227 and OPA2137P, and finally LM6172IN. Couldn't get it to sound quite right. The 49720HA's in the IV with the OPA2227 in the buffer was second best, but there was something weird with the 4kHz range.

Not sure if anyone else experienced this, but regardless of where I put the OPA2137P's it got distortion as soon as I started to turn up the line level a bit (definitely not over doing it). Tried a different OPA2137P just in case it was a defect. Same thing... Didn't have this problem with any of the other op amps.

Good luck... I'm happy for now!

Quote:

Originally Posted by 8-bit thief

I just tried switching out the LM4562 with the LT1364 in the buffer and keeping the stock JRC's in the IV, bad combo with my AD900's, the vocals were brought out too much especially the male vocals, there was extreme sibilance in the male vocals, I had to put the stock LM4562 back after just an hour because I couldn't stand it.

There were some things I did like about it though, like the OPA series of opamps (opa2228, opa2604 etc) the LT1364 has toned down treble compared to the LM4562 but unlike the OPA's there was no loss in detail, so if you're a detail freak that wants to tone down their treble the LT1364 is a good thing to consider.

Another thing I liked is the soundstage, with the LM4562 music always sounds like it's coming from behind me or from the side, with the LT1364 music was coming from the back, the sides as well as the front, the soundstage wasn't as wide however so it's kind of a trade off, overall I preferred the LT1364's SS for making me feel like I'm more surrounded by music.

Quote:

Originally Posted by Shizdan

Well I kept
2x JRC2114D (Stock) in the I/V's and tried

-OPA2111KP - They sounded good but I wasn't all that impressed. Although the soundstage was pretty decent

-OPA2137P - I have these in now and all I can say is wow. They just sound more lively!

My test track is Time - Pink Floyd

Out of all the Op Amps I cant use the following due to my lack of soldering skills!
-OPA2137EA
-OPA2137U
-OPA2107AU

Quote:

Originally Posted by Bizarro

2 x LME49720HA + 1 x LT1364 had a laid back sound, compared to:
2 x LME49720HA + 1 x OPA2107AP which is livelier and defined. There is just a right amount of bass and treble is crisp (in a good way).

Q: What's the proper way to set this thing up for headphone listening?
A:

Quote:

Originally Posted by wali

This is a very basic headphone config for stock Asus Xonar STX/ST. I decided to post this because I was very happy with this config and I was tired of repeating it in every STX-related post. I hope its helpful.

Driver version: 7.12.8.1777
OS: Windows 7 64bit

After installing the driver you have two options, using the line out or the headphone out. The popular opinion used to be/still is that the line out is 'better' but although that's how it looks on the paper, the real life experience of many including myself differs. The built-in headphone amp of Xonar STX is especially well-suited for high impedance headphones.

Setting up the software for headphone listening:

Audio Channel: 2 Channels

Sample Rate: The default setting is 96khz, I don’t know the reason for that, it could be lack of auto sample rate but all my music is 44.1 and I set the sample rate at 44.1 to avoid any resampling. I have the windows sound option for Xonar also set to 24/44.1.

The highest gain setting of 300-600ohms provides the best sound quality, and it’s a perfect match for example with HD580/HD600/HD650, all these headphones have an impedance range of 300ohms to 600ohms.

Use the headphone gain setting at your own risk and make sure you know what you’re doing. This is the most important setting and you must get it right.

DSP mode (bottom right): The only option enabled there should be HF (hi fi) this is very important. HF or hi fi disables all post processing of the signal, for example environment size in Effects option (look below). Environment size creates artificial sound staging and in the process distorts the sound. If you click on any of its options L M S the HF option will be disabled, so make sure HF option is always enabled for optimum fidelity.

Volume Control: Use the volume in Xonar, set the volume at your music player (foobar, winamp etc) at 100%.

Everything else in the driver should be left at default unless needed for some specific reason.

This is what I use for headphone listening. The biggest difference for me was setting the proper gain setting for my headphone and enabling HF.

Please don’t hesitate to share what are your Xonar STX/ST settings and why. But after playing around with this card for three months, this is what I have decided and its very simple and straight forward.

Q: Should I use 192hkz, 96hz, 44.1khz or what?
A: It's probably in your best interests to set the Xonar Control Panel to the sampling rate of the music you are playing back. However, it's up to you to tell if you can hear a difference between the settings. If you don't play any 24/96 sound files, just stick it at 44.1khz. I am currently reviewing this thread to learn more about sketchy bitperfect playback issues, will update when I can!

Q: What's with kernel streaming, ASIO, and all that?
A: That's a larger topic discussed elsewhere, but the cards support both quite well. You should probably use them.

Q: Can this do 3-d gaming sound and surround sound?
A: "For gamers, the Xonar Essence STX supports EAX 2.0, as well as the Asus DS3D GX 2.0, when using digital output. This lets both XP and Vista users play both EAX HD 5.0 and DirectSound 3D games with full surround audio. The EAX 5.0 emulation isn't perfect—we heard occasional quirks like voices picking up unintended echoes—but overall the 3D effect remains convincing and true to the original intent." The card isn't designed to be a gamers card, but for the casual gamer who would want excellent stereo or EAX 2.0 audio, it will fit the bill.

My impressions of the card is that it is totally worth the cost, and a total steal at that. For the individual who listens to most of their music at a computer, it's a no-brainer, unless they want to build a costlier system. Note: there is likely some competition for this card at this point, I will update when I can.

Nice summary. Many of these posts got lost into oblivion in the massive sneak peek thread.

I'd like to add that I've finally settled on 3xLME49720's with my setup. The 49720/JRC2114 setup was good but the dry sound/unforgiving treble and lower soundstage depth became fatiguing after a while.

Kernel streaming and Asio

Both kernel streaming and Asio work well in XP sp3, but I have not tried with 32 bitdepth... The Essence only supports up to 24 bit depth so maybe it doesn't work, or maybe you lose quality. The switch to kernel streaming really improved sound quality, and I recomend it highly...

Kernel Streaming

The whole idea of kernel-streaming and ASIO is to by-pass all Windows interference with SQ, so playing 24 bit shouldn't be a problem. As for changing speeds with varying bit depth and frequensy I haven't noticed any change of speed or similar problems, although I haven't played that many 24 bit flacs...